This disclosure is generally directed to processes for the preparation of titanyl phthalocyanines, especially a highly photosensitive titanyl phthalocyanines like titanyl phthalocyanine Type V, and drum and belt layered photoreceptors, photoconductors thereof, and the like. More specifically, the present disclosure is directed to titanyl phthalocyanine processes where weak acids are selected, and to multilayered flexible or belt imaging members or devices comprised of an optional supporting medium like a substrate, a photogenerating layer containing the prepared titanyl phthalocyanine, and a charge transport layer, including a plurality of charge transports layers, such as a first charge transport layer and a second charge transport layer, an optional adhesive layer, an optional hole blocking or undercoat layer, an optional overcoating layer, and wherein at least one of the charge transport layers contains at least one charge transport component, a polymer or resin binder, and an optional antioxidant.
More specifically, there is illustrated herein in embodiments the incorporation into imaging members of suitable high photosensitivity photogenerating pigments, such as certain titanyl phthalocyanines, which photosensitivity is, for example, from about 10 to about 50 percent higher than that of a similar photoconductor containing as a photogenerating pigment hydroxygallium phthalocyanine Type V; a hole transport layer thereover, and which layer permits the rapid transport of holes, and wherein the photogenerating dispersion is comprised of a photogenerating pigment or pigments of titanyl phthalocyanine prepared as illustrated herein, an optional polymer binder and a chlorinated solvent, such as dichlorinated solvents or monochlorobenzene, which dispersion or mixture is deposited on the photoconductor substrate or other photoconductor layers. The selection of certain halogenated, such as chlorinated, solvents together with using weak acids in the washing of a titanyl phthalocyanine intermediate provides, for example, for the capture of impurities, such as titanium oxide, titanium chloride, or other organic titanates, and thereby generates a high sensitivity titanyl phthalocyanine with lower CDS characteristics than when a weak acid is not used. High dispersion stability and improved potlife are particularly desirable from the manufacturing point of view as the dispersion can be used over an extended period of time, like several days, without a negative impact on the coating process and the photosensitivity of the coated photoreceptors. Poor dispersion stability can result in the pigment settling out quickly to prevent or inhibit a uniform coating of the photogenerating layer. When the photosensitivity of coated photoconductor does not substantially change with the aging of the titanyl phthalocyanine dispersion, then the useful life of the dispersion (potlife) is prolonged allowing efficient utilization of the dispersion materials with minimum waste. Also, the excellent photosensitivity characteristics of the titanyl phthalocyanine obtained can be maintained for suitable periods of time.
Additionally, in embodiments the photoconductors disclosed herein permit minimal undesirable CDS developed image characteristics, excellent and in a number of instances low Vr (residual potential), and allow the substantial prevention of Vr cycle up when appropriate; high stable sensitivity; low acceptable image ghosting characteristics; and desirable toner cleanability.
Also included within the scope of the present disclosure are methods of imaging and printing with the photoconductor devices illustrated herein. These methods generally involve the formation of an electrostatic latent image on the imaging member, followed by developing the image with a toner composition comprised, for example, of thermoplastic resin, colorant, such as pigment, charge additive, and surface additives, reference U.S. Pat. Nos. 4,560,635; 4,298,697 and 4,338,390, the disclosures of which are totally incorporated herein by reference, subsequently transferring the image to a suitable substrate, and permanently affixing the image thereto. In those environments wherein the device is to be used in a printing mode, the imaging method involves the same operation with the exception that exposure can be accomplished with a laser device or image bar. More specifically, the imaging members and flexible belts disclosed herein can be selected for the Xerox Corporation iGEN3® machines that generate with some versions over 100 copies per minute. Processes of imaging, especially xerographic imaging and printing, including digital, and/or color printing are thus encompassed by the present disclosure.
The photoconductors disclosed herein are in embodiments sensitive in the wavelength region of, for example, from about 400 to about 900 nanometers, and in particular from about 650 to about 850 nanometers, thus diode lasers can be selected as the light source. Moreover, the imaging members disclosed herein are in embodiments useful in high resolution color xerographic applications, particularly high-speed color copying and printing processes.